Magnetic fastener driving tool

ABSTRACT

A magnetically attractable threaded fastener is retained in driving engagement with a driving tool by a first permanent magnet, and a magnetically attractable washer is retained on the fastener adjacent the head of the fastener by a second permanent magnet which surrounds both the driving tool and the first permanent magnet. The driving tool may be in the form of a bit for receiving a fastener having a recessed head or may be in the form of a socket for receiving a fastener having a polygonal shaped head.

United States Patent 1 Stillwagon, Jr.

[ 51 Jan. 2, 1973 [54] MAGNETIC FASTENER DRIVING TOOL [75] Inventor: George B. Stillwagon, Jr., Dayton,

[52] US. Cl. ..81/l25, 145/50 DA [51] Int. Cl ..B25b 13/06, B25b 23/12 [58] Field of Search ..l45/50 DA, 50 R; 7/1 Q; 8l/l25 [56] References Cited UNITED STATES PATENTS 3,007,504 ll/l96l Clark ..l45/50 DA 3,392,767 7/1968 Stillwagon, Jr. ..l45/50 DA Primary Examiner-Robert C. Riordon Assistant ExaminerRoscoe V. Parker, Jr. Attorney-Marechal, Biebel, French & Bugg [5 7] ABSTRACT A magnetically attractable threaded fastener is retained in driving engagement with a driving tool by a first permanent magnet, and a magnetically attractable washer is retained on the fastener adjacent the head of the fastener by a second permanent magnet which surrounds both the driving tool and the first permanent magnet. The driving tool may be in the form of a bit for receiving a fastener having a recessed head or may be in the form of a socket for receiving a fastener having a polygonal shaped head.

8 C la inis, 8 DrawingFigures PAIENTEDMZ I 3. 707,894

FIG -4 l/Vl/E/VTUR GEORGE B. STILLWAGON JR.

A TTOR/VE Y8 MAGNETIC FASTENER DRIVING TOOL BACKGROUND OF THE INVENTION In a magnetically attractable driving tool such as disclosed in U.S. Stillwagon, Jr. U.S. Pat. Nos. 3,392,767 and 3,538,792; a thickness oriented elastomeric strip magnet is formed into the shape of a cylinder and is positioned between inner and outer concentric pole pieces. In some embodiments, the inner pole piece is formed by a fastener driving tool bit, and in other embodiments, the outer pole piece is formed by a driving tool having a socket opening for receiving a magnetically attractable threaded fastener having a polygonal shaped head. i

For some fastener applications, it is common to use either a flat washer or a lock washer on the threaded fastener prior to driving the fastener into the receiving body. Usually, the washer is pre-mounted on the fastener and positioned adjacent the head of the fastener. While some embodiments of the driving tools disclosed in the above patents effect some retaining of the washer on the fastener by magnetically attracting the washer through the head of the fastener, it has been found desirable to provide for a more positive retention of the washer on the fastener during the operation of positioning the fastener and washer assembly for drivmg.

SUMMARY OF THE INVENTION The present invention is directed to an improved rotatable magnetic driving tool which not only positively retains the head of a fastener in driving engagement with the tool, but is also effective to retain positively a washer on the fastener adjacent the head of the fastener. The present invention also provides for infinite adjustment of the fastener driving tool to accommodate various types of pre-assembled fasteners and washers.

In accordance with one embodiment of the invention, the fastener driving tool includes a socket opening for receiving the polygonal head of a threaded fastener, and supports a centrally located inner permanent magnet in the form of a rigid bar magnet. A thickness oriented elastomeric strip magnet surrounds the driving tool and is retained by a cylindrical outer pole piece adjustably mounted on the driving tool. The inner magnet is effective to retain the head of the fastener within the socket opening, and the outer permanent magnet is effective to retain the magnetically attractable washer on the fastener adjacent the head of the fastener.

In another embodiment of the invention, the fastener driving tool consists ofa bit for engaging a fastener having a head with a recess. An elastomeric strip magnet surrounds the bit and is confined by an annular inner polepiece which cooperates with the bit to retain the recessed head fastener in driving engagement with the bit. A second thickness oriented elastomeric strip magnet surrounds the inner pole piece and is confined by a cylindrical outer pole piece which cooperates with the inner pole piece and second magnet to retain a magnetic attractable washer adjacent the head of the fastener.

Other features and advantages of the invention will be apparent from the following description, the accompanying drawing and the appended claims.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an axial view of one end of a driving tool constructed in accordance with one embodiment of the invention;

FIG. 2 is an axial section taken generally on the line 22 of FIG. 1;

FIG. 3 is an axial view of the opposite end of the driving tool shown in FIGS. 1 and 2;

FIG. 4 is an elevational view of the driving tool shown in FIGS. 1-3 and with a portion broken away to illustrate the retention of a threaded fastener and washer assembly;

FIG. 5 is a view similar to FIG. 1 and showing another embodiment of the invention;

FIG. 6 is an axial section taken generally on the line 6-6 of FIG. 5;

FIG. 7 is an axial view of the opposite end of the driving tool shown in FIGS. 5 and 6; and

FIG. 8 is a fragmentary section similar to FIG. 4 and illustrating the retention of another form of threaded fastener and washer assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1-4, a tubular socket tool 15 includes a generally square drive socket opening 16 which is adapted to receive a square shank 18 projecting from either a manual or power operated driver (not shown). The forward driving end portion of the socket tool 15 includes a polygonal socket opening 20, having a hexagonal configuration for receiving the hexagonal head portion 21 of the threaded fastener 22 illustrated in the form of a sheet metal screw. A cylindrical sleeve 23 formed of a non-magnetic material such as brass, is press fitted into a cylindrical bore 24 formed within the socket tool 15, and a permanent bar-type magnet 25 is press fitted into the sleeve 23. The forward end portion of the magnet 25 projects into the socket opening 20 and is adapted to engage the head portion 21 of the fastener 22 as shown in FIG. 4.

Surrounding the socket tool 15 is a cylindrical outer or second permanent magnet in the form of a thickness oriented elastomeric strip magnet 26 as disclosed in the above patents. The magnet 26 is retained on the socket tool 15 by a cylindrical tubular sleeve 28 which is mounted for sliding axial adjustment on the socket tool 15 and is retained by a series of three set screws 29. The socket tool 15 and the tubular sleeve 28 form inner and outer pole pieces for the magnet 26, and the forward end surfaces of the tool 15 and sleeve 28 are effective to retain a magnetically attractable washer 30 in a position normal to the axis of the threaded fastener 22 and adjacent the fastener head 21 as illustrated in FIG. 4. That is, the washer 30 effectively closes the magnetic flux path between the forward end of the socket tool 15 and the forward end of the outer tubular sleeve 28.

Referring to FIGS. 5-8 which show another embodiment of the invention, a tool driving member in the form of a screw driving bit 35 having a hexagonal crosssectional configuration includes a driving end portion 36. As shown inFIGS. 6 and 8, the driving end portion 36 of the bit 35 includes driving wings 37 for receiving slotted recesses in the head portion 38 of a screw-type threaded fastener 40. It is to be understood, however, that the driving end portion 36 of the bit 35 may have other configurations for receiving various types of threaded fasteners, as for example, a single driving wing for receiving a straight slotted head of a screw fastener.

Surrounding the tool driving bit 35 is acylindrical first or inner permanent magnet 42 in the form of a thickness oriented elastomeric strip magnet similar to the magnet 26 shown in FIGS. 2 and 4. The strip magnet 42 is retained on the bit 35 by a tubular intermediate sleeve 44 having a forward end portion with a part spherical surface 46 adapted to engage the head portion 38 of the threaded fastener 40 as illustrated in FIG. 8.

The sleeve 44 is secured to the bit 35 by a pair of diametrically opposed set screws 47 which provide for axial adjustment of the sleeve 44 relative to the bit 35 to accommodate fastener heads of various configurations. As illustrated in FlG. 8, the driving bit 35 and the sleeve 44 form respective inner and outer pole pieces for the annular inner strip-magnet 42 and cooperate to retain the head portion 38 of the threaded fastener 40 in driving engagement with the driving end portion 36 of the bit 35. That is, the head portion 38 of the fastener 40 effectively closes the magnetic flux path between the forward end surfaces of the inner and outer pole pieces.

A second or outer cylindrical permanent magnet 48 surrounds the outer surface of the sleeve 44 and is preferably formed from a thickness oriented elastomeric strip magnet in the same manner as the inner annular magnet 42. The magnet 48 is retained on the sleeve 44 by an annular or cylindrical outer sleeve 50 which is adjustably secured to the inner sleeve 44 by a pair of diametrically opposed set screws 51 extending through corresponding holes formed within the elastomeric strip magnet 48. The inner sleeve 44 and the outer sleeve 50 form inner and outer pole pieces for the thickness oriented permanent strip magnet 48, and the forward end surfaces of the sleeves 44 and 50 are effective to retain the magnetically attractable washer 52 in a position adjacent the head 38 of the fastener 40 and normal to the axis of the fastener.

From the drawing and the above description, it is apparent that a rotatable fastener driving tool constructed in accordance with the invention provides desirable features and advantages. For example, both the embodiment shown in FIGS. 1-4 and the embodiment shown in FlGS. -6 are effective not only to retain the head portion of a threaded fastener in driving engagement with the driving tool, but also to retain a magnetically attractable washer on the fastener in a position adjacent the head of the fastener. Thus a fastener driving tool constructed in accordance with the invention is particularly suited for positively picking up, retaining and driving a loose assembly of a threaded fastener and an annular washer in the form of either a flat washer or a split or twisted tooth lock washer. Furthermore, the fastener driving tool of the invention is adapted to be conveniently adjusted to accommodate fasteners having head portions of various configurations and sizes.

While the magnetic driving tools herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of tools, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. A rotatable fastener driving magnetic tool adapted to retain a magnetically attractable threaded fastener and washer assembly, comprising a tool member having means for receiving the head of the fastener in driving engagement, a first inner magnet positioned to attract the fastener and to retain it in said driving engagement with said tool member, a separate outer magnet surrounding said tool member in radially-spaced relation with said inner magnet and in position to attract the washer mounted on the fastener and to retain the washer in a predetermined position on the fastener.

2. A magnetic tool as defined in claim 1 wherein said engaging means of said tool member comprise a socket opening within said tool member, said inner magnet comprises a permanent magnet positioned substantially concentric with said socket opening, and said outer magnet comprises an annular thickness oriented magnet mounted on said tool member and an annular sleeve surrounding said annular magnet and forming an outer pole piece for said annular magnet.

3. A magnetic tool as defined in claim 1 wherein said engaging means of said tool member includes a screw driving bit, said inner magnet comprises an annular magnet mounted on said screw driving bit, an annular intermediate sleeve surrounding said annular magnet, and said second magnet comprises a second annular magnet surrounding said intermediate sleeve and an annular outer sleeve surrounding said second annular magnet.

4. A magnetic tool as defined in claim 3 including means for adjusting said annular intermediate sleeve axially relative to said screw driving bit, and means for adjusting said annular outer sleeve axially relative to said annular intermediate sleeve for accommodating fastener and washer assemblies of different configurations.

5. A magnetic tool as defined in claim 3 wherein said first and second annular magnets each comprise a thickness oriented elastomeric strip magnet.

6. A rotatable fastener driving magnetic tool adapted to retain a magnetically attractable threaded fastener and washer assembly, comprising a tool member having means for receiving the head of the fastener in driving engagement, inner magnetic means positioned within said tool member to attract the fastener and retain it in said driving engagement with said tool member, an outer thickness oriented elastomeric strip magnet in the form of a cylinder surrounding said tool member in radially-spaced relation with said inner magnetic means, and a tubular sleeve surrounding said strip magnet and cooperating herewith to retain the washer in a predetermined position on the fastener.

7. A magnetic tool as defined in claim 6 wherein said inner magnetic means comprise a bar magnet positioned concentrically within said tool member, and a non-magnetic tubular sleeve is positioned between said bar magnet and said tool member for retaining said bar magnet.

8. A magnetic tool as defined in claim 6 wherein said inner magnetic means comprise an inner thickness orientated elastomeric strip magnet in the form of a cylinder and surrounding said tool member, and an intermediate sleeve is positioned between said inner strip magnet and said outer strip magnet and forms both an outer pole piece for said inner magnet and an inner pole piece for said outer magnet. 5 

1. A rotatable fastener driving magnetic tool adapted to retain a magnetically attractable threaded fastener and washer assembly, comprising a tool member having means for receiving the head of the fastener in driving engagement, a first inner magnet positioned to attract the fastener and to retain it in said driving engagement with said tool member, a separate outer magnet surrounding said tool member in radially-spaced relation with said inner magnet and in position to attract the washer mounted on the fastener and to retain the washer in a predetermined position on the fastener.
 2. A magnetic tool as defined in claim 1 wherein said engaging means of said tool member comprise a socket opening within said tool member, said inner magnet comprises a permanent magnet positioned substantially concentric with said socket opening, and said outer magnet comprises an annular thickness oriented magnet mounted on said tool member and an annular sleeve surrounding said annular magnet and forming an outer pole piece for said annular magnet.
 3. A magnetic tool as defined in claim 1 wherein said engaging means of said tool member includes a screw driving bit, said inner magnet comprises an annular magnet mounTed on said screw driving bit, an annular intermediate sleeve surrounding said annular magnet, and said second magnet comprises a second annular magnet surrounding said intermediate sleeve and an annular outer sleeve surrounding said second annular magnet.
 4. A magnetic tool as defined in claim 3 including means for adjusting said annular intermediate sleeve axially relative to said screw driving bit, and means for adjusting said annular outer sleeve axially relative to said annular intermediate sleeve for accommodating fastener and washer assemblies of different configurations.
 5. A magnetic tool as defined in claim 3 wherein said first and second annular magnets each comprise a thickness oriented elastomeric strip magnet.
 6. A rotatable fastener driving magnetic tool adapted to retain a magnetically attractable threaded fastener and washer assembly, comprising a tool member having means for receiving the head of the fastener in driving engagement, inner magnetic means positioned within said tool member to attract the fastener and retain it in said driving engagement with said tool member, an outer thickness oriented elastomeric strip magnet in the form of a cylinder surrounding said tool member in radially-spaced relation with said inner magnetic means, and a tubular sleeve surrounding said strip magnet and cooperating herewith to retain the washer in a predetermined position on the fastener.
 7. A magnetic tool as defined in claim 6 wherein said inner magnetic means comprise a bar magnet positioned concentrically within said tool member, and a non-magnetic tubular sleeve is positioned between said bar magnet and said tool member for retaining said bar magnet.
 8. A magnetic tool as defined in claim 6 wherein said inner magnetic means comprise an inner thickness orientated elastomeric strip magnet in the form of a cylinder and surrounding said tool member, and an intermediate sleeve is positioned between said inner strip magnet and said outer strip magnet and forms both an outer pole piece for said inner magnet and an inner pole piece for said outer magnet. 